Detection and characterization of clostebol sulfate metabolites in Caucasian population

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Vol. 1022; pp. 54 - 63
• Main Authors: Balcells, Georgina, Pozo, Oscar J., Garrostas, Lorena, Esquivel, Argitxu, Matabosch, Xavier, Kotronoulas, Aristotelis, Joglar, Jesús, Ventura, Rosa
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2016; Elsevier
• Subjects: Anabolic steroid; Anabolitzants; Chromatography, Liquid - methods; Clostebol; Derivatives; Doping analysis; Doping in Sports; European Continental Ancestry Group; Excretion; Humans; LC–MS/MS; Limit of Detection; Male; Metabolisme; Metabolites; Metabòlits; Monitoring; Strategy; Sulfate metabolites; Sulfates; Tandem Mass Spectrometry - methods; Testosterona; Testosterone; Testosterone - analogs & derivatives; Testosterone - metabolism; Testosterone - pharmacokinetics; Testosterone - urine; Urine; Sulfate metabolites; Clostebol; Anabolic steroid; LC–MS/MS; Doping analysis
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/j.jchromb.2016.03.028

•Clostebol metabolism in man may have inter-individual and inter-ethnic variations.•Sixteen clostebol sulfate metabolites were detected in Caucasian individuals urine.•S1a is a long-term metabolite detectable up to 31 days after administration.•S1a was characterized by GC–MS as 4ξ-chloro-5α-androst-3β-ol-17-one 3β-sulfate.•Inclusion of S1a metabolite to doping control screening methods is advisable. Anabolic androgenic steroids (AAS) are synthetic testosterone derivatives which undergo extensive metabolism in man. Differences in the excretion of phase II metabolites are strongly associated with inter-individual and inter-ethnic variations. Sulfate metabolites have been described as long-term metabolites for some AAS. Clostebol is the 4-chloro derivative of testosterone and the aim of the present study was the evaluation of clostebol sulfate metabolites in Caucasian population by LC–MS/MS technology. Clostebol was orally administered to four healthy Caucasian male volunteers, and excretion study urines were collected up to 31 days. Several analytical strategies (neutral loss scan, precursor ion scan and selected reaction monitoring acquisitions modes) were applied to detect sulfate metabolites in post-administration samples. Sixteen sulfate metabolites were detected, five of them having detectability times above 10 days (S1a, S2a, S3b, S3g and S4b). Interestingly, metabolite S1a could be detected up to the last collected sample of all excretion studies and it was characterized by LC–MS/MS and GC–MS as 4ξ-chloro-5α-androst-3β-ol-17-one 3β-sulfate. Thus, monitoring of S1a improves the detection time of clostebol misuse with respect to the commonly monitored metabolites, excreted in the glucuronide fraction. Importantly, this new metabolite can be incorporated into recently developed LC–MS/MS screening methods base on the direct detection of phase II metabolites.